added guide

index.html

@@ -38,6 +38,13 @@
     #forcearea span {
       font-size: 12px;
     }
+    
+    #guide {
+      margin: 20% auto;
+      width: 220px;
+      padding: 20px;
+      border: 1px dashed #c3c3c3;
+    }
   </style>
 </head>
 
@@ -47,6 +54,9 @@
     <div id="buttonarea">
       <button id="tareButton">Tare</button>
     </div>
+    <div id="guide">
+      Place object here
+    </div>
   </div>
 
   <script>